add hydra pagedCollection info to dcat feed

[nvdk]

it would be nice to add information on pagination of the dcat feed using hydra, see for example the following extract from http://oppnadata.se/catalog.ttl?page=1

<http://oppnadata.se/catalog.ttl?page=1> a hydra:PagedCollection ;
    hydra:firstPage "http://oppnadata.se/catalog.ttl?page=1" ;
    hydra:itemsPerPage 100 ;
    hydra:lastPage "http://oppnadata.se/catalog.ttl?page=4" ;
    hydra:nextPage "http://oppnadata.se/catalog.ttl?page=2" ;
    hydra:totalItems 371 .